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BIOL 240 Microbiology > Unit 7 - Bacterial MVPs > Flashcards

Unit 7 - Bacterial MVPs Flashcards

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1
Q

proteobacteria (gram, characteristics, metabolism)

A
  • often most commonly encountered bacteria
  • related to mitochondria
  • metabolically diverse
    – chemolithotrophs
    – chemoorganotrophs
    – phototrophs
    (many diff metabolisms, diff sources of e-)
  • morphologicaly diverse
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2
Q

what are the 5 phylogenetic groups of proteobacteria

A

alpha, beta, gamma, delta, epsilon
α β γ δ ε

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3
Q

proteobacteria named after Greek god ___

A

Proteus (as changeable and dynamic as the ocean)

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4
Q

proteobacteria lineage/categories (include metabolism type)

A

ancestral phototroph->

phototroph:
- alpha purple bacteria
- gamma purple bacteria
- beta purple bacteria

loss of photosynthetic ability:
- epsilon purple bacteria (all chemoorganotrophs)
- delta purple bacteria (all chemoorganotrophs)

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5
Q

proteobacteria - type of photosynthesis, inhibited by? wavelength determined by?

A

anoxygenic photosynthesis
- photosynthesis is inhibited by O2 (but some can grow aerobically)
- not like cyanobacteria!
- wavelengths determined by specific bacteriochlorophylls and carotenoids (many diff colours)

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6
Q

purple sulfur bacteria blooms

A

photoautotrophs of Gammaproteobacteria
- oxidize H2S to S^0 during photosynthetic CO2 reduction in anoxic lake water
- accumulates in inclusion bodies
- photolithoautotrophs
- stored in periplasm or outside cells, disappears when oxidized to sulfate

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7
Q

Winogradsky column description

A
  • mud column, developed by Sergei Winogradsky
  • photoautotrophs of Gammaproteobacteria
  • high sulfur preferred by purple sulfur bacteria, low sulfur preferred by purple non-sulfur bacteria
  • sulfur as a source of e-
  • light as energy
  • CO2 as carbon source
  • H2S source due to anaerobic respiration (with SO4^2- as e- acceptor)
  • sulfate reducers make sulfide, which floats up to help higher organisms survive
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8
Q

Winogradsky column order (bottom to top)

A

BOTTOM (H2S)
- sulfate reducers, fermenters, cellulolytic bacteria
- green sulfur bacteria
- purple sulfur bacteria
- purple non-sulfur bacteria
- cyanobacteria and algae
water
air
TOP (O2)

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9
Q

methanotrophs and methylotrophs (oxidation, env)

A

methylotrophs oxidize C1 compounds
- no C-C bonds (non-organic)
- e.g., CH4, HCOOH

methanotrophs are methylotrophs capable of oxidizing methane (CH4 to methanol)
- methane monooxygenase (MMO)
- intracytoplasmic membranes! (surface area)
- obligate C1 utilizers
- obligate aerobes, often microaerophilic
- widespread in soil and water, morphologically diverse

methanotroph env
- aquatic and terrestrial habitats
- often at interface between anoxic (where methane is formed) and oxic (needed for respiration) zones
– frequently observed at the thermocline (e.g., lake water columns)
- found in cattle rumen, swamps
– although high CH4, O2 often too low

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10
Q

methanotrophs vs methylotrophs

A

Methanotrophs are methylotrophs capable of oxidizing methane (CH4 to methanol)

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11
Q

nitrifiers (rxn, characteristics)

A

NH3 -> NO2 -> NO3
- use reduced N compounds as energy sources (e- donors)
- intracytoplasmic membranes also
- capable of autotrophic growth (chemolithoautotrophs)
- scattered in 4 of 5 subdivisions

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12
Q

nitrifiers subdivisions (species)

A
  • scattered in 4 of 5 subdivisions

Nitrosococcus and Nitrosomonas (Nitroso-)
- ammonia oxidizers
- ammonia monooxygenase

Nitrobacter and Nitrospira (Nitro-)
- nitrile oxidizers
- nitrile oxidase

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13
Q

What is FISH? Details, probe colour meaning, rxn

A
  • detecting nitrifying bacteria in activated sewage sludge by FISH
  • two types of bacteria co-occur in nature
  • fluorescent dye-tagged phylogenetic probes
    – Red: ammonia-oxidizing bacteria
    – Green: nitrite-oxidizing bacteria
    NH3 -(red)-> NO2 -(green)-> NO3
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14
Q

what is the species exception to the nitrification process?

A

Comammox bacteria (Nitrospira)
NH3 -> NO2 -> NO3
- complete nitrification

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15
Q

Pseudomonads characteristics (taxonomy, morphology feature, env, etc)

A

heterogeneous group with evolving taxonomy
- Pseudomonas recently split into Pseudomonas, Burkholderia, Ralstonia, Commamonas, etc

aerobic chemoorganoheterotrophs
- polar flagella (distinguishes from enterics)

nutritionally and ecologically versatile
- soil, water, eukaryotic hosts
- may infect plants and/or animals

some are fluorescent!
- Pseudomonas aeruginosa or Pseudomonas fluorescens
- Pyoverdin produced as a siderophore (sequester iron from host)

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16
Q

___, ____, and ____ use internal membranes for energy generation

A

nitrifiers, purple bacteria, methanotrophs use internal membranes for energy generation

17
Q

both purple sulfur and purple nonsulfur bacteria can use sulfur for ___

A

e-

18
Q

N2 fixers characteristics

A

free-living, N2-fixing bacteria
- fix N2 into biomass; most are aerobes
- nitrogenase (reduces N2 to Nh3) is irreversible inactivated by O2
- thick capsule slime layer, very high respiration rate maintain low internal conc of O2

agrobacterium and rhizobia (not free-living)
- members of Alphaproteobacteria:
– Family: Rhizobiaceae
– Gram-neg, aerobic rods
– generally plant-associated

  • incl Agrobacterium (parasitism)
    – Crown-gall disease (tumours)
    – don’t fix N
    – Transfer DNA (T-DNA) invades eukaryotic genome (inter-kingdom), allowed by “vir region”; also digests opines made by plants through opine catabolism genes
  • Rhizobium, Sinorhizobium, Azorhizobium, Mesorhizobium, Bradyrhizobium (mutualism)
    – symbiotic nitrogen-fixers
    – root nodules
    – associated with legumes!!!
19
Q

rhizobium (root nodule formation)

A
  • plants express flavonoids
  • bacterial nod genes expressed
  • infection thread formed to invade root
  • nodule forms, providing a low O2 env
  • root cells form leghemoglobin to assist

plant provides C compounds and photosynthase to bacteria, while bacteria provide ammonium

step summary: flavonoids, nod factor, root curl, infection

20
Q

enterics

A

enteric bacteria
- all found in Gammaproteobacteria (e.g., Salmonella, E coli)
- facultative, oxidase negative, peritrichous flagella
- coliforms are gram-neg, non-spore forming, lactose-fermenting, producing acid and gas at 37 deg C
– some associated with feces (fecal coliforms) and can be warning signs of pathogens
– many enterics are pathogens

21
Q

Deltaproteobacteria (2, characteristics)

A

Bdellovibrio bacteriovorus
- chemoorganoheterotroph
- “bdello” = leech “bacteriovorus” = bacteria eater
- small, HIGHLY motile (vibroid shape)
– 100 cell lengths per second
- preys on other bacteria (Gram-neg)
– virus-like life cycle

Gliding Myxobacteria
- complex behaviour and development
- large chromosome
- INTERcellular communication
- vegetative cells have gliding motility (lyse other cells for nutrients, chemoorganoheterotrophs)
- slime trails
- nutrient limitation leads to differentiation, cooperation (requires quorum)
– multicellular, pigmented fruiting bodies (antioxidant)
- fruiting bodies filled with myxospores
env: decaying wood, dung pellets (visible w magnifying glass)

22
Q

Bdellovibrio life cycle

A
  • Hydrolytic enzymes produced in periplasm
  • 3-6 progeny per lysis, more from larger cells, filaments
  • Attachment, penetrate periplasm, degrades cytoplasm/cell membrane, consuming cell material, elongation inside, divide to make more, prey lysis
23
Q

Myxobacteria life cycle

A

fruiting body needs (1) starvation (2) quorum (enough organism mass to form fruiting body)

vegetative cycle can aggregate into mound -> fruiting body -> make myxospores -> germinate

chemical induction can also make vegetative cells into myxospores

24
Q

firmicutes and actinobacteria are also known as?

A

firmicutes = low GC
actinobacteria = high GC

25
Q

spores in this topic refer to? meaning?

A

refer to endospores, so ones with must all be Gram-pos

26
Q

Gram-pos bacteria (non-sporulating)

A

Staphylococcus and Micrococcus
- aerobic growth, catalase positive
- resistant to drying + high salt
- 7.5% NaCl can select for them
- often pigmented

Staphylococcus
- firmicutes division (low GC)
- found on animals (SKIN)
Micrococcus
- actinobacteria division (high GC)
- isolated objects, dust, SKIN

Lactic acid bacteria
- rods and cocci
- aerotolerant anaerobes
– no ETC (no respiration)
– substrate level phosphorylation only (fermentation)
- complex nutritional requirements (fastidious, limited biosynthetic capacity)

27
Q

which species of lactic acid bacteria are in processes of human interest? for what?

A
  • Streptococcus pyogenes (necrotizing fasciitis)
  • Streptococcus pneumoniae (bacterial pneumonia)
  • Fermented food products (buttermilk, cheese: e.g., Lactococcus)
  • Dental caries
28
Q

homofermenters vs heterofermenters

A

lactic acid bacteria

homofermenters only make lactic acid

heterofermenters make lactic acid, ethanol, and CO2

29
Q

Gram-positive bacteria (sporulating)

A

Bacillus group (facultative or obligate aerobes)
- can degrade polymers (amylases, nucleases, lipases)
- produce antibiotics (related to sporulation process)
- some make crystal toxins
– kill insect larvae
– Bacillus thuringiensis (BT toxin)
- some can infect humans, other animals
– Bacillus anthracis (anthrax)

Clostridium group (strict anaerobes; no e- transport)
- diverse fermentation substrates and products
- important for industry (Acetone, etc)
- some fix N2 (no need to protect nitrogenase from O2 since anaerobic)
- some make toxins that cause human disease

30
Q

agricultural importance of Gram-pos bacteria (sporulating)

A

Bacillus thuringiensis

parasporal body
- crystalline protoxin (Cry protein)
- converted to toxin in larval insect gut (why it’s called pro-toxin
- BT toxin
- endospore next to the crystal

31
Q

botox species

A

Clostridium botulinum

32
Q

3 positions of endspores

A

terminal
subterminal
central

33
Q

actinobacteria (high GC Gram-pos)

A

tuberculosis (Robert Koch) - Mycobacterium, tuberculosis

  • contain mycolic acids in cell wall (waxy)
    – long fatty acids
    – acid-fastness (need heat for dye to penetrate; hard for drugs to penetrate)

many are human pathogens
- Mycobacterium leprae (leprosy)
– hosts: humans and armadillo (temp)
– can’t be cultured
- Mycobacterium tuberculosis
– hard to culture

resistant to many cheicals

34
Q

Mycobacterium species and most other actinobacteria are ?

A

normally occurring soil bacteria

many are harmless, many can cause disease

35
Q

filamentous actinobacteria

A

incl Streptomyces and relatives
- filamentous, branching mycelia
- desiccation-resistant spores
– CONIDIA (formed in sporophores)
- GEOSMINS = make soil/earthy smell
- make antibiotics (stimulates growth at low conc)

36
Q

sporophores aka? what do they grow into? steps?

A

AKA aerial hypha
grow into spores (conidia)

growth phase, tip curls, partitioning of tip, cell walls thicken and constrict, spores mature

37
Q

what is used for taxonomy for Streptomyces groups?

A

type of sporebearing structures

38
Q

Cyanobacteria (charcateristics)

A

gram-neg

  • distant phylogenetic relationship to gram-pos bacteria
  • cell envelope structure similar to gram-neg
  • oxygenic phototrophs
  • gliding motility
  • morphologically diverse
  • have chlorophyll a (like algae and plants)
  • also have phycobilins (bag-like membranes)
    – accessory pigment
    – phycocyanins (blue)
    – phycoerythrin (red)
  • photosynthetic pigments within thylakoid membrans
39
Q

what do some cyanobacteria make? (unique & cool) rxn

what do they do?

A

some filamentous cyanobacteria make heterocysts!
- differentiated cells capable of N2 fixation, have thick wall to exclude O2 (nitrogen fixation)
- not used for anything else
N2 -> NH3 –> Glutamine

vegetative cells around it obtain organic carbon from CO2 by light energy capture, then sends fixed carbon to heterocysts

BIOL 240 Microbiology (10 decks)

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